<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=Windows-1252">
</head>
<body>
<div style="direction: ltr; font-family: Aptos, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
Hi Sachin</div>
<div style="direction: ltr; font-family: Aptos, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div style="direction: ltr; font-family: Aptos, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
For QS, the U(eff) value for the Mg s orbitals is applied to all its s orbitals, i.e. to the 2s and 3s concurrently, which explains your results. The N value is ignored (<a href="https://manual.cp2k.org/trunk/CP2K_INPUT/FORCE_EVAL/SUBSYS/KIND/DFT_PLUS_U.html#CP2K_INPUT.FORCE_EVAL.SUBSYS.KIND.DFT_PLUS_U.N" data-outlook-id="66f925dc-ecac-4333-bc4f-27fbf0999153">as
described</a>) unless it is a PWDFT run using the SIRIUS library.</div>
<div style="direction: ltr; font-family: Aptos, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div style="direction: ltr; font-family: Aptos, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
The orbital occupations calculated with CP2K usually differ from the ones obtained with PW codes and thus the appropriate U(eff) values are also different.</div>
<div style="direction: ltr; font-family: Aptos, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div style="direction: ltr; font-family: Aptos, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
HTH</div>
<div style="direction: ltr; font-family: Aptos, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div style="direction: ltr; font-family: Aptos, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
Matthias</div>
<div style="direction: ltr; font-family: Aptos, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div id="mail-editor-reference-message-container">
<div class="ms-outlook-mobile-reference-message skipProofing" style="direction: ltr;">
</div>
<div style="padding: 3pt 0in 0in; border-width: 1pt medium medium; border-style: solid none none; border-color: rgb(181, 196, 223) currentcolor currentcolor;">
<div class="ms-outlook-mobile-reference-message skipProofing" style="text-align: left; font-family: Aptos; font-size: 12pt; color: black;">
<b>From: </b>cp2k@googlegroups.com <cp2k@googlegroups.com> on behalf of Sachin Ramesh <sachinadityaramesh@gmail.com><br>
<b>Date: </b>Tuesday, 26 May 2026 at 12:29<br>
<b>To: </b>cp2k <cp2k@googlegroups.com><br>
<b>Subject: </b>[CP2K:22248] DFT+U in CP2K 2024.3<br>
<br>
</div>
</div>
<div class="ms-outlook-mobile-reference-message skipProofing">Hello everyone, </div>
<div class="ms-outlook-mobile-reference-message skipProofing" style="direction: ltr;">
<br>
</div>
<div class="ms-outlook-mobile-reference-message skipProofing">As part of an ongoing study, I am investigating how the electronic energy levels of the MgO(001) surface change when different Hubbard U corrections are applied to Mg and O orbitals (both occupied
and unoccupied states).<br>
<br>
In CP2K (2024.3), when a U_eff value of 1.5 eV is applied to the Mg-3s and Mg-2s orbitals, the calculated:</div>
<div class="ms-outlook-mobile-reference-message skipProofing" style="direction: ltr;">
<br>
</div>
<div class="ms-outlook-mobile-reference-message skipProofing">* HOMO (VBM) value, and<br>
* HOMO–LUMO (band-gap) value</div>
<div class="ms-outlook-mobile-reference-message skipProofing"><br>
turn out to be identical.</div>
<div class="ms-outlook-mobile-reference-message skipProofing"><br>
However, performing similar calculations in Quantum ESPRESSO gives different values for the VBM and the band gap. I would like to understand whether this behavior arises from:<br>
1. differences in the DFT+U implementations/projector definitions between CP2K and Quantum ESPRESSO, or<br>
2. a possible issue in my CP2K setup or interpretation of the results.<br>
<br>
I have attached the corresponding CP2K input and output files.<br>
<br>
Any insights would be greatly appreciated.</div>
<div class="ms-outlook-mobile-reference-message skipProofing" style="direction: ltr;">
<br>
</div>
<div class="ms-outlook-mobile-reference-message skipProofing">Sachin </div>
<div class="ms-outlook-mobile-reference-message skipProofing">--<br>
You received this message because you are subscribed to the Google Groups "cp2k" group.<br>
To unsubscribe from this group and stop receiving emails from it, send an email to
<a href="mailto:cp2k+unsubscribe@googlegroups.com" data-outlook-id="a4a4c9c4-2442-4571-8b66-3633bfb284dd">
cp2k+unsubscribe@googlegroups.com</a>.<br>
To view this discussion visit <a href="https://groups.google.com/d/msgid/cp2k/8d90223a-1862-4801-b6b0-e371b862c32dn%40googlegroups.com?utm_medium=email&utm_source=footer" data-outlook-id="ee8f1cbe-b386-4ba8-a2d7-d4847d46a8d4">
https://groups.google.com/d/msgid/cp2k/8d90223a-1862-4801-b6b0-e371b862c32dn%40googlegroups.com</a>.</div>
</div>
</body>
</html>
<p></p>
-- <br />
You received this message because you are subscribed to the Google Groups "cp2k" group.<br />
To unsubscribe from this group and stop receiving emails from it, send an email to <a href="mailto:cp2k+unsubscribe@googlegroups.com">cp2k+unsubscribe@googlegroups.com</a>.<br />
To view this discussion visit <a href="https://groups.google.com/d/msgid/cp2k/ZR2P278MB11463A75FED22D03964DE93CF40B2%40ZR2P278MB1146.CHEP278.PROD.OUTLOOK.COM?utm_medium=email&utm_source=footer">https://groups.google.com/d/msgid/cp2k/ZR2P278MB11463A75FED22D03964DE93CF40B2%40ZR2P278MB1146.CHEP278.PROD.OUTLOOK.COM</a>.<br />